very simple, reddit markdown parser

parse.swift

//
//  RedditParser.swift
//  redditParser
//
//  Created by sonson on 2015/09/22.
//  Copyright © 2015年 sonson. All rights reserved.
//

import Foundation

let regex = try! NSRegularExpression(pattern: "(\\n{0,1}\\s*\\*\\s)|(~~([^\\s]+?)~~)|(\\*\\*([^\\s^\\*]+?)\\*\\*)|(\\*([^\\s^\\*]+?)\\*)|(\\[(.+)\\]\\(([%!$&'()*+,-./0123456789:;=?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~]+)\\))|(\\^([^\\s\\^]+))|(https{0,1}://[%!$&'()*+,-./0123456789:;=?@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~]+)", options: NSRegularExpressionOptions.CaseInsensitive)

let parser = NSAttributedStringMarkdownParser()

public enum Attribute {
    case Link(String, Int, Int)
    case Bold(Int, Int)
    case Italic(Int, Int)
    case Superscript(Int, Int)
    case Strike(Int, Int)
}

extension String {
    func redditParse() -> String {
        let casted = self as NSString
        let copied:NSMutableString = (self as NSString).mutableCopy() as! NSMutableString
        
        
        let results = regex.matchesInString(self, options: NSMatchingOptions(), range:NSMakeRange(0, casted.length))
        
//        for result in results {
////            for i in 0...(result.numberOfRanges-1) {
////                print((self as NSString).substringWithRange(result.rangeAtIndex(0)))
////            }
//        }
        
        results.reverse().forEach { (result) -> () in
            if result.rangeAtIndex(1).length > 0 {
                // *
                let r = NSMakeRange(result.rangeAtIndex(1).location, result.rangeAtIndex(1).length)
                copied.replaceCharactersInRange(r, withString: "\n・")
            }
            if result.rangeAtIndex(2).length > 0 {
                // ~~ ~~
                let r1 = NSMakeRange(result.rangeAtIndex(2).location, result.rangeAtIndex(2).length)
                let r2 = NSMakeRange(result.rangeAtIndex(3).location, result.rangeAtIndex(3).length)
                let sub = copied.substringWithRange(r2)
                copied.replaceCharactersInRange(r1, withString: sub)
            }
            if result.rangeAtIndex(4).length > 0 {
                // * *
                let r1 = NSMakeRange(result.rangeAtIndex(4).location, result.rangeAtIndex(4).length)
                let r2 = NSMakeRange(result.rangeAtIndex(5).location, result.rangeAtIndex(5).length)
                let sub = copied.substringWithRange(r2)
                copied.replaceCharactersInRange(r1, withString: sub)
            }
            if result.rangeAtIndex(6).length > 0 {
                // []()
                let r1 = NSMakeRange(result.rangeAtIndex(6).location, result.rangeAtIndex(6).length)
                let rangeOfTitle = NSMakeRange(result.rangeAtIndex(7).location, result.rangeAtIndex(7).length)
                let rangeOfLink = NSMakeRange(result.rangeAtIndex(8).location, result.rangeAtIndex(8).length)
                let title = copied.substringWithRange(rangeOfTitle)
                let url = copied.substringWithRange(rangeOfLink)
                copied.replaceCharactersInRange(r1, withString: "<a href=\(url)>\(title)</a>")
//                copied.replaceCharactersInRange(r1, withString: sub)
            }
            if result.rangeAtIndex(9).length > 0 {
                // ^
                let r1 = NSMakeRange(result.rangeAtIndex(9).location, result.rangeAtIndex(9).length)
                let r2 = NSMakeRange(result.rangeAtIndex(10).location, result.rangeAtIndex(10).length)
                let sub = copied.substringWithRange(r2)
                copied.replaceCharactersInRange(r1, withString: "^^^\(sub)")
            }
            if result.rangeAtIndex(11).length > 0 {
                // ^
                let r1 = NSMakeRange(result.rangeAtIndex(11).location, result.rangeAtIndex(11).length)
                let r2 = NSMakeRange(result.rangeAtIndex(11).location, result.rangeAtIndex(11).length)
                let sub = copied.substringWithRange(r2)
                copied.replaceCharactersInRange(r1, withString: "<a href=\(sub)>\(sub)</a>")
            }
        }
        
        return copied as String
    }
    
    func  redditParse3() -> String {
//    NSAttributedStringMarkdownParser* parser = [[NSAttributedStringMarkdownParser alloc] init];
//    NSAttributedString* string = [parser attributedStringFromMarkdownString:
//    @"This is __rad__."];
        
//        let attr = parser.attributedStringFromMarkdownString(self)
        
        let str = NSString.convert(self as String)
        
        return str
    }
    
    func redditParse2() -> String {
        let casted = self as NSString
        let copied:NSMutableString = (self as NSString).mutableCopy() as! NSMutableString
        
        
        let results = regex.matchesInString(self, options: NSMatchingOptions(), range:NSMakeRange(0, casted.length))
        
        var buf = ""
        var pointer = 0
        
        var attrs = [Attribute]()
        
        results.forEach { (result) -> () in
            if result.rangeAtIndex(1).length > 0 {
                if result.rangeAtIndex(1).location - pointer > 0 {
                    let r0 = NSMakeRange(pointer, result.rangeAtIndex(1).location - pointer)
                    buf.appendContentsOf(copied.substringWithRange(r0))
                }
                buf.appendContentsOf("\n・")
                pointer = (result.rangeAtIndex(1).location + result.rangeAtIndex(1).length)
            }
            if result.rangeAtIndex(2).length > 0 {
                if result.rangeAtIndex(2).location - pointer > 0 {
                    let r0 = NSMakeRange(pointer, result.rangeAtIndex(2).location - pointer)
                    buf.appendContentsOf(copied.substringWithRange(r0))
                }
                // ~~ ~~
                let r2 = NSMakeRange(result.rangeAtIndex(3).location, result.rangeAtIndex(3).length)
                let sub = copied.substringWithRange(r2)
                buf.appendContentsOf(sub)
                
                attrs.append(Attribute.Strike(buf.characters.count - sub.characters.count, sub.characters.count))
                
                pointer = (result.rangeAtIndex(2).location + result.rangeAtIndex(2).length)
            }
            if result.rangeAtIndex(4).length > 0 {
                if result.rangeAtIndex(4).location - pointer > 0 {
                    let r0 = NSMakeRange(pointer, result.rangeAtIndex(4).location - pointer)
                    buf.appendContentsOf(copied.substringWithRange(r0))
                }
                // * *
                let r2 = NSMakeRange(result.rangeAtIndex(5).location, result.rangeAtIndex(5).length)
                let sub = copied.substringWithRange(r2)
                buf.appendContentsOf(sub)
                
                attrs.append(Attribute.Bold(buf.characters.count - result.rangeAtIndex(5).length, result.rangeAtIndex(5).length))
                
                pointer = (result.rangeAtIndex(4).location + result.rangeAtIndex(4).length)
            }
            if result.rangeAtIndex(6).length > 0 {
                if result.rangeAtIndex(6).location - pointer > 0 {
                    let r0 = NSMakeRange(pointer, result.rangeAtIndex(6).location - pointer)
                    buf.appendContentsOf(copied.substringWithRange(r0))
                }
                // * *
                let r2 = NSMakeRange(result.rangeAtIndex(7).location, result.rangeAtIndex(7).length)
                let sub = copied.substringWithRange(r2)
                buf.appendContentsOf(sub)
                
                attrs.append(Attribute.Italic(buf.characters.count - result.rangeAtIndex(7).length, result.rangeAtIndex(7).length))
                
                pointer = (result.rangeAtIndex(6).location + result.rangeAtIndex(6).length)
            }
            if result.rangeAtIndex(8).length > 0 {
                if result.rangeAtIndex(8).location - pointer > 0 {
                    let r0 = NSMakeRange(pointer, result.rangeAtIndex(8).location - pointer)
                    buf.appendContentsOf(copied.substringWithRange(r0))
                }
                let rangeOfTitle = NSMakeRange(result.rangeAtIndex(9).location, result.rangeAtIndex(9).length)
                let rangeOfLink = NSMakeRange(result.rangeAtIndex(10).location, result.rangeAtIndex(10).length)
                let title = copied.substringWithRange(rangeOfTitle)
                let url = copied.substringWithRange(rangeOfLink)
                
                buf.appendContentsOf(title)
                
                attrs.append(Attribute.Link(url, buf.characters.count - title.characters.count, title.characters.count))
                
                pointer = (result.rangeAtIndex(8).location + result.rangeAtIndex(8).length)
            }
            if result.rangeAtIndex(11).length > 0 {
                if result.rangeAtIndex(11).location - pointer > 0 {
                    let r0 = NSMakeRange(pointer, result.rangeAtIndex(11).location - pointer)
                    buf.appendContentsOf(copied.substringWithRange(r0))
                }
                // ^
                let r2 = NSMakeRange(result.rangeAtIndex(12).location, result.rangeAtIndex(12).length)
                let sub = copied.substringWithRange(r2)
                
                buf.appendContentsOf(sub)
                
                attrs.append(Attribute.Superscript(buf.characters.count - sub.characters.count, sub.characters.count))
                
                pointer = (result.rangeAtIndex(11).location + result.rangeAtIndex(11).length)
            }
            if result.rangeAtIndex(13).length > 0 {
                if result.rangeAtIndex(13).location - pointer > 0 {
                    let r0 = NSMakeRange(pointer, result.rangeAtIndex(13).location - pointer)
                    buf.appendContentsOf(copied.substringWithRange(r0))
                }
                // ^
                let r2 = NSMakeRange(result.rangeAtIndex(13).location, result.rangeAtIndex(13).length)
                let sub = copied.substringWithRange(r2)
                buf.appendContentsOf(sub)
                
                attrs.append(Attribute.Link(sub, buf.characters.count - sub.characters.count, sub.characters.count))
                
                pointer = (result.rangeAtIndex(13).location + result.rangeAtIndex(13).length)
            }
        }
        
        if copied.length - pointer > 0 {
            let r0 = NSMakeRange(pointer, copied.length - pointer)
            buf.appendContentsOf(copied.substringWithRange(r0))
        }
        
        attrs.forEach { print($0) }
        
        print(buf.characters.count)
        
        return buf as String
    }
}